New addition to the Damen dredging portfolio

Damen has added a new dredger to its dredging portfolio. Named the Plain Suction Dredger, this latest addition to the dredging range has been designed to be used for free flowing sand, which means that it therefore does not require a cutter unit. Damen is well known for its comprehensive range of cutter suction dredgers and the introduction of the new Plain Suction Dredger completes the Damen dredging portfolio perfectly. The new addition has been designed by the specialist Damen dredging team, and Mark van ‘t Veld, one of the specialists that developed the Plain Suction Dredger, explains the philosophy behind the concept.

Designed for practical use

“What we often see is Cutter Suction Dredgers being used in circumstances for which they have not been designed”, he says. “A cutter suction dredger uses its cutter to mechanically loosen compacted soil, but when the soil is free flowing, this cutting action is superfluous. Bear in mind that cutters need power and so consume fuel. The dredge head is also a costly item of hydraulically powered equipment and the way that the cutter is used to grind away soils requires the vessel itself to be made much heavier. When all this force is not required, it is much more practical and economical to use a Plain Suction Dredger.”

How to work with a Plain Suction Dredger

“Operating a Plain Suction Dredger is very different compared to handling a Cutter Suction Dredger,” says Mark van ‘t Veld. “The Plain Suction Dredger is a practical dredging tool and is really easy to operate. It requires only one operator, who is in control of the entire operation. The main aim of the operator is to ensure that dredge production remains consistently high. To achieve this the sand mining head requires a constant flow of bottom material. The Plain Suction Dredger has been designed to work in non-compacted free flowing sand, and so it is equipped with a jet water assisted head to ensure that a good mixture concentration is reached. This sand mining head is held steadily in the sediment, with the head being gradually lowered until the maximum dredging depth is achieved. The dredger can pull itself gently forwards using its winches, but in general it makes use of the natural phenomenon of breaching. The dredger does not continuously pivot around spuds, which a Cutter Suction Dredger would do. Instead, electrically-powered winches move the dredger forward or sideways when the flow of sand slightly diminishes. This practical design keeps the entire installation light and compact.”

Compact and modular

In summary, a Plain Suction Dredger is a stationary dredger with a central pivoting suction pipe and a high capacity sand mining head. The dredge pump and diesel drive are situated in the main pontoon, while a compact diesel generator set is located on the main pontoon. The air conditioned control cabin delivers full functionality to the operator, so he does not need to access the engine room. In front of the control cabin, the electrical winches that control the manoeuvring and the suction pipe are shielded by fixed railings for safety. Two wide side pontoons not only add buoyancy but most importantly ensure a stable vessel. Finally, the entire dredger is dismountable, enabling it to be fitted into just three standard containers.

What is typical dredging work for a PSD 350?

For any Plain Suction Dredger, its primary function is bulk sediment removal. This can be sand dredging in a river that continuously brings down sediment from upstream mountain ranges. While other typical tasks can be constant dredging to ensure that irrigation canals are kept free of blockages. Maintenance dredging works like these are often located in remote areas, but that is no problem for the dismountable Plain Suction Dredger. Due to its compact and modular design, it can be transported in only three 40 feet open top containers, or on three trucks. Due to the limited unit weight of the few components, reassembly of the dredger and further set-up on site is quite straightforward.

Safe and green

Dredging specialist Mark van ‘t Veld continues: “What we have aimed to do is to create a practical dredger that is safe and simple to operate. At dawn, the operator starts the genset on deck, gets into his operating cabin and gets to work! There is no need for him to enter the engine room or be near the winches at any time. All these are simple safety precautions. Maintenance duties are low as there is no hydraulic system on board, and no wear and tear of cutter heads or spud hoisting systems, additional reasons why the operator does not have to move about the vessel.”

Added to that is the reduced environmental impact of the dredger. “Of course, people will point out that diesel engines are still central to its operations, so how can it be environmentally-friendly?” says Mark. “But do bear in mind that not only do we use some 60% less steel in the build than a similar CSD, the PSD 350 also requires 55% lower transport volume, its on-board oil volume is reduced by 95%, and it delivers a lower fuel consumption with a higher production. And did I mention earlier that we can pump fine sand over at least 1.5 kilometres?” adds Mark with a smile.

Ready for trial runs

At present the first Plain Suction Dredger PSD 350 is being commissioned at the Damen Dredging yard. Once completed, the Plain Suction Dredger will be ready for its first dredging job, and Mark is more than happy to travel with the dredger to see it outperforming his wildest dredge pump predictions.